Histologic Features of Mycobacterial Spindle Cell Pseudotumors

作者：Julianne M. Szczepanski, Joshua A. Lieberman, Laura W. Lamps, Raul S. González, Yue Xue, Xuchen Zhang, Osman H. Yilmaz, John Hart, Thomas Krausz, José G. Mantilla, Jonathan B. McHugh, Maria Westerhoff · 发表于：The American Journal of Surgical Pathology · 年份：2024 · DOI：10.1097/pas.0000000000002234 · 被引用次数：6 · 研究领域：Mycobacterium research and diagnosis、Tuberculosis Research and Epidemiology、Diagnosis and treatment of tuberculosis

Mycobacterial spindle cell pseudotumors (MSPs) are a rare and diagnostically challenging manifestation of non-tuberculous mycobacterial (NTM) infections. Proper recognition of these pseudotumors is important because they are treatable and benign. In this study, we evaluated the morphologic patterns of MSPs to improve their pathologic identification. Clinical and morphologic features of 14 MSPs were analyzed. Histologic factors evaluated included the architectural growth pattern of spindled or epithelioid macrophages, granulomas and their location within the lesion, neutrophilic microabscesses, multinucleated giant cells, necrosis, and effacement of background tissue. The composition of inflammatory infiltrates, organism density by acid-fast staining, and stromal changes were also assessed. In addition, 8 of 14 cases underwent molecular microbiology identification by a clinical amplicon-sequencing assay for non-tuberculous mycobacteria. MSP sites included 2 bowel, 10 lymph nodes, 1 liver, and 1 extremity. Cases with available clinical history (n=10) all occurred in immunocompromised patients. All demonstrated effacement of normal structures with spindled cells arranged in a storiform or fascicular architectural pattern. In addition, all cases showed lymphocytic inflammation, with prominent concurrent neutrophilic inflammation in 50% (7/14) of cases. Other morphologic findings included foamy histiocytes (64%, 9/14), peripherally situated granulomas (21%, 3/14), and neutrophilic...